THREE-PHASE POTENTIAL TRANSFORMER

摘要

PURPOSE:To obtain a three-phase potential transformer (PT) of a small type, enabled to reduce the establishment area, and enabled to form a board to accommodate the PT in a small type by a method wherein the respective high-voltage terminals of the adjoining high-voltage lead- out parts of the PTs of two pieces, and the coils of high-voltage windings to face to the respective high-voltage terminals thereof are prevented from application of a voltage between them. CONSTITUTION:When high-voltage terminals V1A, U1B of two pieces are connected by a connecting lead 12, the outer peripheral sides of the respective high-voltage terminals V1A, U1B and coils 8A2, 8B1 are made to have the same electric potential. Therefore, even when the high- voltage lead-out part 3A2 of a PT 1A provided with the high-voltage terminal V1A approaches the surface of a synthetic resin 7B layer at the outside of the coil 8B1 of an adjoining PT 1B, and moreover even when the high-voltage lead-out part 3B1 of the PT 1B provided with the high-voltage terminal U1B approaches the surface of a synthetic resin 7A layer at the outside of the coil 8A2 of the PT 1A on the other side, because no voltage is applied between them, partially electric discharge is not generated in a gap part. Moreover, an interphase voltage is applied between the outer peripheral sides of the coils 8A1, 8A2, and lead-out leads 10A, 10B, while because only the synthetic resins 7A, 7B having high dielectric strength are interposed between them, generation of partially electric discharge at the part thereof is reduced. Accordingly, because a weak point part in regard to insulation is not generated even when the two PTs 1A, 1B are juxtaposed, the establishment area can be reduced.